1. Field of the Invention
The present invention relates to a full-automatic washing machine, and more particularly to a full-automatic washing machine having a vibration damping assembly which can effectively prevent an undesirable vibration
2. Prior Arts
Generally, washing machines are classified into a full-automatic washing machine and a semi-automatic washing machine according to the operating manner.
As is well known, the full-automatic washing machine carries out washing, rinsing, and dehydrating operations about washing objects in a single spin tub so that there is no need to provide a separated dehydration tub for extracting a washing liquid contained in washed washing objects. On the contrary, the semi-automatic washing machine has a washing tub and a separated dehydration tub to carry out the washing and dehydrating operations, respectively.
Recently, the full-automatic washing machines are widely used as a household washing machine.
However, since the spin tub having relatively large volume is rotated at a high speed, the full-automatic washing machine generates a vibration while it carries out the washing and dehydrating operations.
In particular, when the washing objects are unevenly distributed within the spin tub, an extreme vibration may be created so that not only a loud noise is generated but also, in extreme case, the washing machine moves from its initial position.
To overcome the above mentioned problems, there has been effort to provide a full-automatic washing machine which can prevent an undesirable vibration thereof.
FIG. 3 shows such a conventional full-automatic washing machine 300 having an assembly 330 for damping a vibration.
As shown in FIG. 3, the conventional full-automatic washing machine comprises a body 305 having a plurality of projecting parts 307 formed in an upper portion of its inner wall, an outer tub 310 having a plurality of protuberances 312 formed in a lower portion of its outer wall, a spin tub 320 mounted in outer tub 310 so as to receive washing objects, a motor 340 for rotating spin tub 310, and a plurality of assemblies 330 for damping a vibration caused by rotation of spin tub 320.
Each of projecting parts 307 and protuberances 312 has a recess (not shown) for fitting vibration damping assembly 330.
Vibration damping assembly 330 includes a supporting member 332 fitted to the recess of projecting part 307 and formed with a perforated hole at a center thereof, a rod 334, one end of which is inserted in the perforated hole and the other end of which is fitted to the recess of protuberances 312, a housing 336 having an open end and disposed at an underside of protuberances 312 in order to damp a vibration of outer tub 310, and a cap 339 inserted into the open end of housing 336.
The conventional full-automatic washing machine 300 has four vibration damping assemblies 300.
The operation of the conventional full-automatic washing machine 300 being constructed as described above is as follows.
Firstly, in the event of a washing operation, when a user pushes an operating button (not shown) disposed in an upper portion of washing machine 300 on, a control unit (such as micro computer) generates a signal for washing operation, and thereby motor 340 is driven. The driving force of motor 340 is transmitted to pulsator 322 disposed in a lower portion of spin tub 320 so that pulsator 322 is rotated. As pulsator 322 rotates, a liquid flow having a swirl shape is generated in spin tub 320. The liquid flow that has been generated in spin tub 320 impacts on washing objects, which have been loaded in spin tub 320, and thereby the washing objects are washed.
Then, when the washing operation has finished, washing liquid that has been supplied to outer tub 310 is drained into an exterior of washing machine 300. In this state, the control unit generates a signal for dehydrating operation, and thereby motor 340 is driven again. At this time, the driving force of motor 340 is transmitted to spin tub 320 so that spin tub 320 is rotated.
As spin tub 320 rotates, the washing objects loaded in spin tub 320 are subjected to centrifugal force so that the washing objects are forced radially outward of spin tub 320, i.e., toward a side wall of spin tub 320, and thereby washing liquid contained in the washed washing objects is drained into an exterior of washing machine 300 through a plurality of openings formed in the side wall of spin tub 320.
During the washing and dehydrating operations, a vibration is inevitably happened in washing machine 300. In particular, the vibration may occur more extremely during the dehydration operation since spin tub 320 having a relatively large size is rotated at a high speed.
To reduce the vibration, conventional washing machine 300 comprises a plurality of vibration damping assemblies 330. Vibration damping assemblies 330 are regularly disposed around a circumference of outer tub 310 so as to effectively damp the vibration caused by high-speed rotation of spin tub 320.
That is, the vibration that has been generated by rotation of spin tub 320 or pulsator 322 is transmitted to housing 312 of vibration damping assembly 330, which is in contact with protuberance 312 of outer tub 310, through outer tub 310. At this time, spring 338 disposed in housing 312 is repeatedly compressed and expanded according to the vibration so that the vibration can be damped. The damped vibration is transmitted to support member 332 through rod 334 connected to housing 336 so that only a reduced vibration is transmitted to body 305 of washing machine 300.
However, the conventional automatic washing machine 300 being constructed as described above has the following disadvantages.
Firstly, vibration damping assembly 330 as mentioned above consists of a plurality of parts so that the construction of vibration damping assembly 330 is complex and assembling of vibration damping assembly 330 is difficult.
Further, when the washing objects are unevenly distributed within spin tub 320, a relatively heavier vibration is transmitted to an upper portion of body 305 of washing machine 300 so that a loud noise may happen.
Furthermore, a relatively larger space is needed in washing machine 300 to install vibration damping assembly 330.
Accordingly, there has been a necessity to provide an automatic washing machine having a vibration damping assembly which has a simple construction, which can effectively prevent the vibration, and which does not need a large installation space.